A zooming optical system suitable for a photographic cameras, electronic still cameras, video cameras or the like has been proposed (e.g. Patent Document 1). In recent years, requirements for preventing ghosts and flares, which would diminish optical performance, are becoming increasingly stricter for zooming optical systems suitable for photographic cameras, electronic still cameras, video cameras or the like, therefore higher performance is also demanded for an anti-reflection film formed on a lens surface, and to meet this demand, multilayer film designing technology and multilayer film deposition technology are continuously advancing (e.g. see Patent Document 2).